Facing Problem in Importing USR02 using RFC_Read_Table

I am trying to import USR02 table of child system  from the parent system.But getting Error as Table Not available in my main program.Kindly help.

Code :

data :

lv_table type DD02L-TABNAME,

lv_rfcdest type  RFCDEST,

lt_options type STANDARD TABLE of rfc_db_opt,

lt_fields type STANDARD TABLE of rfc_db_fld,

lt_data type STANDARD TABLE of tab512.

lv_rfcdest = 'SR4CLNT800'.

WRITE : /.

lv_table  = 'USR02'.

CALL FUNCTION 'RFC_READ_TABLE'

  DESTINATION lv_rfcdest

  IMPORTING

    QUERY_TABLE = lv_table

    ex_usr02    = lv_table

  TABLES

    OPTIONS     = lt_options

    FIELDS      = lt_fields

    DATA        = lt_data.

IF SY-SUBRC <> 0.

* MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO

*         WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.

ENDIF.

exit.